Nein Nein Nein Lives AKA Return of the Living Undead

First deck I tried with the Hallow's End Doom in the Tomb event. Focuses on summoning multiple Sylvanas Windrunner through Nine Lives and N'Zoth, the Corruptor. 

Has extremely good late game overall, between N'Zoth, the Corruptor, Zul'jin and allows you to refill your deck with Dire Frenzy on the Unleash the Beast token or Vicious Scalehide.

Included Secret Package which can be tweaked with other/different secrets in any way you want.

Some card selections

Vicious Scalehide - Early game card that helps fight for the board against aggressive decks.

Master's Call - With the low number of minions on the deck, you can rather reliably draw what you need with it, serving as a late game "fill your hand with Wyverns" card.

Spider Bomb - Another Deathrattle for N'Zoth, the Corruptor and Nine Lives. While not essential, it can help making these cards become less dead draws in case Sylvanas Windrunner decides to be in the bottom of the deck.

Call of the Wild - Just a good card with Zul'jin, even though it is easily replaceable.

Other cards you can try

Shimmerfly - Early game decent Deathrattler that refill's your hand.

Springpaw - Another decent early game option if you're being overrun with aggro.

Tracking - Becomes a bit less good in such a late game focused deck, but it is still one of the best cards in the entire game.

Lock and Load - You can go full meme. You have the spells for it (might wanna drop Emperor Thaurissan to get even more cards).

Other deathrattle cards, including Ursatron, Savannah Highmane, SN1P-SN4P and Khartut Defender for a more midrangy route on the deck. You can drop Master's Call and Call of the Wild, for example, though I have done no testing regarding this option. You can also go full Mech, with Replicating Menace, Oblivitron, Mechanical Whelp and Fireworks Tech, for example.